backlight: gpio-backlight: Add DT support

Signed-off-by: Denis Carikli <denis@eukrea.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/Documentation/devicetree/bindings/video/backlight/gpio-backlight.txt b/Documentation/devicetree/bindings/video/backlight/gpio-backlight.txt
new file mode 100644 (file)
index 0000000..321be66
--- /dev/null
+++ b/Documentation/devicetree/bindings/video/backlight/gpio-backlight.txt
@@ -0,0 +1,16 @@
+gpio-backlight bindings
+
+Required properties:
+  - compatible: "gpio-backlight"
+  - gpios: describes the gpio that is used for enabling/disabling the backlight.
+    refer to bindings/gpio/gpio.txt for more details.
+
+Optional properties:
+  - default-on: enable the backlight at boot.
+
+Example:
+       backlight {
+               compatible = "gpio-backlight";
+               gpios = <&gpio3 4 GPIO_ACTIVE_HIGH>;
+               default-on;
+       };

diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
index 81fb127..a2eba12 100644 (file)
--- a/drivers/video/backlight/gpio_backlight.c
+++ b/drivers/video/backlight/gpio_backlight.c
@@ -13,6 +13,8 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
 #include <linux/platform_data/gpio_backlight.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
@@ -23,6 +25,7 @@ struct gpio_backlight {
 
        int gpio;
        int active;
+       int def_value;
 };
 
 static int gpio_backlight_update_status(struct backlight_device *bl)
@@ -60,6 +63,29 @@ static const struct backlight_ops gpio_backlight_ops = {
        .check_fb       = gpio_backlight_check_fb,
 };
 
+static int gpio_backlight_probe_dt(struct platform_device *pdev,
+                                  struct gpio_backlight *gbl)
+{
+       struct device_node *np = pdev->dev.of_node;
+       enum of_gpio_flags gpio_flags;
+
+       gbl->gpio = of_get_gpio_flags(np, 0, &gpio_flags);
+
+       if (!gpio_is_valid(gbl->gpio)) {
+               if (gbl->gpio != -EPROBE_DEFER) {
+                       dev_err(&pdev->dev,
+                               "Error: The gpios parameter is missing or invalid.\n");
+               }
+               return gbl->gpio;
+       }
+
+       gbl->active = (gpio_flags & OF_GPIO_ACTIVE_LOW) ? 0 : 1;
+
+       gbl->def_value = of_property_read_bool(np, "default-on");
+
+       return 0;
+}
+
 static int gpio_backlight_probe(struct platform_device *pdev)
 {
        struct gpio_backlight_platform_data *pdata =
@@ -67,10 +93,12 @@ static int gpio_backlight_probe(struct platform_device *pdev)
        struct backlight_properties props;
        struct backlight_device *bl;
        struct gpio_backlight *gbl;
+       struct device_node *np = pdev->dev.of_node;
        int ret;
 
-       if (!pdata) {
-               dev_err(&pdev->dev, "failed to find platform data\n");
+       if (!pdata && !np) {
+               dev_err(&pdev->dev,
+                       "failed to find platform data or device tree node.\n");
                return -ENODEV;
        }
 
@@ -79,14 +107,22 @@ static int gpio_backlight_probe(struct platform_device *pdev)
                return -ENOMEM;
 
        gbl->dev = &pdev->dev;
-       gbl->fbdev = pdata->fbdev;
-       gbl->gpio = pdata->gpio;
-       gbl->active = pdata->active_low ? 0 : 1;
+
+       if (np) {
+               ret = gpio_backlight_probe_dt(pdev, gbl);
+               if (ret)
+                       return ret;
+       } else {
+               gbl->fbdev = pdata->fbdev;
+               gbl->gpio = pdata->gpio;
+               gbl->active = pdata->active_low ? 0 : 1;
+               gbl->def_value = pdata->def_value;
+       }
 
        ret = devm_gpio_request_one(gbl->dev, gbl->gpio, GPIOF_DIR_OUT |
                                    (gbl->active ? GPIOF_INIT_LOW
                                                 : GPIOF_INIT_HIGH),
-                                   pdata->name);
+                                   pdata ? pdata->name : "backlight");
        if (ret < 0) {
                dev_err(&pdev->dev, "unable to request GPIO\n");
                return ret;
@@ -103,17 +139,25 @@ static int gpio_backlight_probe(struct platform_device *pdev)
                return PTR_ERR(bl);
        }
 
-       bl->props.brightness = pdata->def_value;
+       bl->props.brightness = gbl->def_value;
        backlight_update_status(bl);
 
        platform_set_drvdata(pdev, bl);
        return 0;
 }
 
+#ifdef CONFIG_OF
+static struct of_device_id gpio_backlight_of_match[] = {
+       { .compatible = "gpio-backlight" },
+       { /* sentinel */ }
+};
+#endif
+
 static struct platform_driver gpio_backlight_driver = {
        .driver         = {
                .name           = "gpio-backlight",
                .owner          = THIS_MODULE,
+               .of_match_table = of_match_ptr(gpio_backlight_of_match),
        },
        .probe          = gpio_backlight_probe,
 };